BA (mod) 2004 (Trinity College Dublin) Zoology;
MSc 2005 (University of York) Zooarchaeology;
PhD 2010 (QUB)
Archaeology and Palaeoecology
School of Geography, Archaeology and Palaeoecology (GAP)
Queen’s University Belfast
Belfast, BT7 1NN
Northern Ireland, UK
+44 (0)28 9097 5295
14C as a tool to trace terrestrial carbon in a complex lake: implications for food-web structure and carbon cycling
Primary production of autochthonous carbon in a highly alkaline lake is partially based on dissolved inorganic carbon (DIC) containing radiocarbon (14C) -- free 'dead' carbon from the weathering of carbonaceous bedrock. The low 14C activity yields an artificial age offset from the modern atmosphere leading the samples to appear hundreds of years older than their actual modern age. With terrestrial inputs likely to increase, the origin and utilisation of allochthonous carbon in the food-web is in question; is it recent 'modern' carbon or from 'old' soil carbon stocks.
Carbon and nitrogen Stable Isotope Analysis (SIA) has been used to show utilisation of terrestrial carbon by zooplankton and fish. The differences in the isotopic signatures of terrestrial and aquatic carbon are generally accepted; however SIA alone yields limited information. Natural abundance 14C can help untangle riverine and lacustrine zooplankton food webs. The methods can be used in various lake types, such as Lower Lough Erne, an alkaline, humic lake. Variation in stable isotope values and 14C activity of components of the freshwater system have determined the origin of carbon in Lower Lough Erne. Autochthonous, 'detrital' (resistant to decay) or 'labile' (partially decayed) terrestrial -- have been found to support all levels of the food web.
In addition, carbon sources in lake sediment have been identified. In Lower Lough Erne, c.64% of carbon in sediment is derived from detrital (resistant to decay) terrestrial carbon, probably originating in older peat in the catchment. I am also working in Rostherne Mere, an alkaline, eutrophic lake analysing sediment using radiocarbon to identify and quantify carbon sources in this eutrophic lake.
I have shown that the radiocarbon method can determine the influence of terrestrial inputs and their character (decayed or labile) on the carbon storage potential of a lake.
E.M., P.J. Reimer, and R.H. Foy . 2015. Young, Old, and Weathered Carbon—Part 1: Using Radiocarbon and Stable Isotopes to Identify Carbon Sources in an Alkaline, Humic Lake. Radiocarbon, 2015. 57(3). 407-423
Keaveney, E.M., P.J. Reimer, and R.H. Foy. 2015. Young, Old, and Weathered Carbon—Part 2: Using Radiocarbon and Stable Isotopes to Identify Terrestrial Carbon Support of the Food Web in an Alkaline, Humic Lake. Radiocarbon, 2015. 57(3). 425-438
Keaveney E.M., Reimer P.J. 2012. Understanding the variability in freshwater radiocarbon reservoir offsets: a cautionary tale Journal of Archaeological Science 39 (5), 1306-1316
Keaveney E. M. (2010) 'Fish bones from Tulsk, Co. Roscommon' Commercial Report for Discovery Programme.
Keaveney E. M. (2010) 'Additional Fish Remains from Rothe House' Commercial Report for Kilkenny Archaeology.
Keaveney, E. M. (2009) 'Fish bones from Killeen Castle' in Baker C The Archaeology of Killeen Castle, Co. Meath, Bray: Wordwell Press
Keaveney, E. M. (2008) 'Fish Remains from Rothe House' Commercial Report for Kilkenny Archaeology.
Keaveney, E. M. and Parks, R. L. (2006) 'Fish Remains from Earith Campground, Cambridgeshire' Reports for the Centre of Human Palaeoecology, University of York
Royal Irish Academy Charlemont Award (https://www.ria.ie/sites/default/files/2016.pdf)
Researcher Co-I on NERC small grant (NE/I01666X/1)
I completed my undergraduate BA (mod) in Zoology in 2004 at Trinity College, Dublin. I became interested in archaeology when I worked on a fish bone assemblage from excavations at Temple Bar in Dublin. I went on to York University in the U.K. to complete an MSc degree in Zooarchaeology where I specialised in fish bone identification. I have completed my PhD at Queen's University, Belfast. I investigated radiocarbon reservoir offsets from freshwater fishbone in Britain and Ireland in order to calibrate the offset and discovered that the variability seen, while preventing correcting the reservoir offset could be used to investigate utilisation of terrestrial carbon by freshwater fish. I now work in various investigating carbon cycling in lakes and their sediments and terrestrial carbon support of the food web. I am also involved in the construction of Ramped Pyrolysis facilities at the 14CHRONO Centre.